warfare conditions revealed that 10–20 percent reported (in the absence of actual exposure to chemical weapons) moderate to severe psychological symptoms, including anxiety, claustrophobia, and panic (Fullerton and Ursano, 1990).
For vestibulocerebellar testing, Yokoyama and colleagues (1998a) used computerized posturography on sarin cases and controls. Computerized posturography is a standard means of assessing vestibular function by placing subjects in the middle of a platform and measuring how their movements displaced the platform (via pressure transducers connected from the platform to a computer). The study found significant impairment only in female cases (n = 9) who performed more poorly (with their eyes open) in their ability to maintain postural sway and their center of gravity when they moved at low frequencies (0–1 Hz) in the anterior– posterior direction. Female patients also performed more poorly in the area of sway (i.e., the area on the platform over which the test subject moves to maintain balance). None of the postural sway tests were abnormal in male cases (n = 9). The authors viewed their findings as suggestive of a gender difference in a “delayed” effect of acute sarin poisoning on the vestibulocerebellar system. Their characterization of this effect as “delayed” is questionable, since there is no evidence of this postural testing having been performed at an earlier point after sarin exposure. Thus, the effect may be chronic, rather than delayed.
The Tokyo sarin experience confirms that acute exposure to sarin leads to the acute cholinergic syndrome. Sarin exposure at high levels can be fatal if cardiopulmonary compromise or convulsions ensue. Visual disturbances are frequent sequelae of the acute exposure, particularly in individuals with high-level exposure. Neurophysiological testing of a small group of asymptomatic sarin-exposed individuals does show chronic changes in visual and event-related evoked potentials and vestibulocerebellar function months after the acute syndrome has subsided. These neurophysiological data are suggestive of subtle, persistent CNS effects from sarin. Except for digit symbol test abnormalities, significant cognitive deficits were not detected.
As explained earlier in this chapter, CIA–DoD modeling determined that U.S. troops located within 25 km of the Khamisiyah weapons site demolition in March 1991 may have been exposed to low or intermediate levels of sarin (CIA–DoD, 1997). U.S. troops did not report acute cholinergic symptoms at the time, but the possibility of low-level, asymptomatic exposures cannot be discounted. In a series of studies on members of a naval battalion (n = 249) called to active duty for the Gulf War, Haley and Kurt (1997) found that veterans who believed themselves to have been exposed to chemical weapons14 were more
Based on self-reports about their perceptions of CW exposure, rather than any evidence of symptomatology. Their geographical and temporal location in relation to the Khamisiyah demolition site was not reported. The questionnaire was sent to participants in 1994, before DoD reported that chemical weapons exposure could have occurred.